Project Summary Motivational interviewing (MI) theory posits certain measures of client language serve as key mechanisms of behavior change. Specifically, increased change talk, or statements supporting movement toward healthy behavior, and decreased sustain talk, or statement supporting maintenance of unhealthy behavior, should lead to reductions in risky alcohol use. While findings support aspects of this technical hypothesis of MI, there are a number of limitations to the current study of client language. Of note, large amounts of in-session language go unexamined and the current MI model lacks a theory guiding session content, particularly in contexts where clients are not ready to discuss changes in drinking. Behavioral economics (BE) theory assumes the reinforcing value of a substance is a function of the benefit/cost ratio of substance use in relation to the benefit/cost of other available activities; thus BE provides a structure by which to understand the value of alcohol and other reinforcing behaviors. BE also identifies delayed reward discounting as a critical factor associated with value appraisal of behavior. The proposed research aims to integrate cutting-edge MI process research with BE theory with the goal of developing an innovative, theoretically-driven conceptualization of client language associated with college alcohol use and response to brief intervention. Comprised of BE and MI experts, the proposed research team will develop and test an enhanced coding system that uses a parallel decision-making process involving multiple independent choices for each client language utterance: one for motivational state, another for behavioral target (e.g., talking about an alternative substance-free behavior such as spending more time studying vs. the identified target behavior of alcohol use reduction), and a third related to temporal orientation (e.g., discussing future goals vs. present circumstances). During the initial development stage, MI session recordings from three completed randomized controlled trials will be coded using the novel client language variables and compared to conventional definitions of change talk and sustain talk to examine convergent, divergent, and incremental validity. Next, using recordings from another two completed randomized controlled trials, the novel coding system will examine client language as a predictor of response to an innovative BE clinical application compared to a traditional MI intervention. Finally, using data from all five original trials, we will examine conditional models of client language as predictors of treatment response. The current study has significant potential to enhance efforts to reduce risky young adult drinking and inform clinical training and practice.